Generally, I’m not convinced that there is any difference between a healthy living system, and what tales singled out as an antifragile system. All healthy organisms, ecosystems, biomes etc are strengthened by moderate stressors because they are adaptive (learning ) systems. Here, designing aikido is a great example of how teleodynamic (see Terrence Deacon) work. Learning and adaptation in evolution is in large part a process of building up of constraints against which asymmetries can be released in a controlled way allowing useful( to the organism) work against spontaneous (generally destructive to living process) release. Put another way, evolution of the biosphere is a process of building up ever more diverse pathways for using the second law of thermodynamics against itself. If the person hit you before you invented Akido, the force of the blow would be distributed kinetically in the region around the strike resulting in some damage to you. After inventing Akido, you are able to redirect that energy into doing useful (to you) work against your attacker.